leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

KVM: SVM: Move GHCB unmapping to fix RCU warning

Browse Source 
When an SEV-ES guest is running, the GHCB is unmapped as part of the
vCPU run support. However, kvm_vcpu_unmap() triggers an RCU dereference
warning with CONFIG_PROVE_LOCKING=y because the SRCU lock is released
before invoking the vCPU run support.

Move the GHCB unmapping into the prepare_guest_switch callback, which is
invoked while still holding the SRCU lock, eliminating the RCU dereference
warning.

Fixes: 291bd20d5d ("KVM: SVM: Add initial support for a VMGEXIT VMEXIT")
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <b2f9b79d15166f2c3e4375c0d9bc3268b7696455.1620332081.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Tom Lendacky
2021-05-06 15:14:41 -05:00
committed by Paolo Bonzini
parent 368340a3c7
commit ce7ea0cfdc
3 changed files with 5 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
arch/x86/kvm/svm/sev.c
View File

@@ -2197,7 +2197,7 @@ vmgexit_err:
return -EINVAL;
}
static void pre_sev_es_run(struct vcpu_svm *svm)
void sev_es_unmap_ghcb(struct vcpu_svm *svm)
{
if (!svm->ghcb)
return;
@@ -2233,9 +2233,6 @@ void pre_sev_run(struct vcpu_svm *svm, int cpu)
struct svm_cpu_data *sd = per_cpu(svm_data, cpu);
int asid = sev_get_asid(svm->vcpu.kvm);
/* Perform any SEV-ES pre-run actions */
pre_sev_es_run(svm);
/* Assign the asid allocated with this SEV guest */
svm->asid = asid;